time is telling

A few days ago Dr Fleury wrote me a quite short message, with just the subject line “time is telling” and a paper attached :

Who moves whom during primitive streak formation in the chick embryo, Manli Chuai and Cornelis J. Weijer, HFSP J. 2009 April; 3(2): 71–76. Published online 2009 March 31. doi: 10.2976/1.3103933.

comment

Just posted this to Pharyngula at the “An ontogeny of toilet drain behavior” thread

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Very nice from Dr Fleury to finally inform us of what L2/R2 could be. Never late to do well. The funny thing is that he commented here but haven’t send me a message about it! That’s weird. I’m asking for evidence concerning L2R2 since august 2007.

Let’s see what we have here anyway.

The first pair of vortices Fleury claims as R1L1 are shown by CuiC et al [Dev Biol. 2005 Aug 1;284(1):37-47. doi:10.1016/j.ydbio.2005.04.021, during stages ~1-3+.

For more than 2 years the presence of the R2L2 vortices was assumed to be visible during the same developmental period and modeled as the result of a single phenomenon.

The second pair of vortices Fleury claims as R2L2, presumably shown here, are situated between stages ~8-9+. They traveled in time!

Assuming that we have evidence for R2L2, the model presented by Fleury describing simultaneously the two pairs, R1L1 and R2L2, must be wrong and he should recall his paper (doi: 10.1051/epjap/2009033) and clarify this point (along with correcting everything else) before submitting it again.

Unfortunately, it seem's that the cell trajectories are manually spotted, the green color must not mislead anybody to confuse it as GFP expression, which is the case with Weijer's lab experiments. Manual spotting is not the best technique to follow a particular cell population during a process where everything is moving in 3D. Not even ink or membrane dyes were used!

The first gif file even as annotated by Fleury don't show any vortex.

The second gif file is even worse, it is obvious that the 2D depiction of the vortices is just false, sorry Dr Fleury, the cells/tissues movement is in 3D, you can't just get a projection in 2D and try to make it look as you would like it to be. This seems to be a recurrent problem. The animation starts when the 8th pair of somites is forming at stage 9+, always faraway in time.

Let me summarize Dr Fleury:

IF those are the R2L2, the vortices contributing to the formation of the hindlimbs THEN

the previous positioning at stages 1 through 3+ was false, as I have argued the last 2+ years

AND

the published models are false [cteappv (2009) & epmag (2005)]

AND that have nothing to do anymore with a 2D flow you claim to be at the origin of the tetrapods.

Now, we don’t really think we have evidence from a 2D manual projection of a 3D moving structure, in the absence of a tissular marker.

And I wonder what you will prefer, drop your model which assumes a (almost) 2D cellular layer and a hyperbolic flow forming simultaneously the four vortices, or try to get more consistent evidence (if any available).

old URL & old rule coming back

[repost]

So, Vincent Fleury always unable to deal with the scientific content of his publication seek other means to shut down critics.

It will be rather difficult.

cteappv is back

I had a short exchange of messages with Mark from the ToS Reports department of WordPress.com.

First of all I would like to thank Mark, not for restoring my account, but, for the clarity of his replies, which is not often the case with people I had to communicate for other issues on various blogging platforms.

Anyway, I haven’t decided yet if I will continue with WordPress.com, confirm my migration back to Blogger, or have a WordPress blog hosted by some other provider than WordPress.com. I’ll need legal advice for the matter

The comment with Fleury’s IP and professional e-mail is hold for editing and it will certainly not contain the same info when it will come back. The info is available for who needs it via channels that don’t involve WordPress.com, but I think it’s not necessary anymore as Fleury’s movement tends to indicate that he really is the author of the weird comments posted at PZ’s and certainly the message PZ published.

I don’t understand why providing the IP and (already public) e-mail of someone could be threatening for his privacy. Wikipedia, including the French section, should be covered by complaints (maybe they are and they don’t give a shit about them).

Anyway, this is not the subject of this blog, just an accident, so I’ll resume with the critic of Fleury’s paper ASAP.

L2/R2

The second anniversary of my request for help to position the four vortices Fleury claims is rapidly approaching and I was looking around for something relevant to make a celebration poster.

I opened The Mechanisms Underlying Primitive Streak Formation in the Chick Embryo, by Manli Chuai and Cornelis J. Weijer¹ for inspiration and of course Fleury’s webpage with his english short presentation.

pharyngulitis

Is the surge of affluence due to the mention of ones blog even at the comments of Pharyngula.

Welcome guys.

Feel comfortable but be afraid, I’m the one manipulating the Master!
Using noodly appendages of course.

pre-cteappv Oops 090713

This is a pre-cteappv Oops and I start wondering how Fleury manage to find journals with so poor review process as to let go to press such mistakes.

This one is from An Elasto-Plastic Model of Avian Gastrulation, Vincent Fleury, Organogenesis 2:1, 6-16, 2005.

4 The paleontological point of view

There is not as much paleontology as one would expect by the title of the chapter. Mostly paleontology is an excuse to further discuss developmental biology, except for subsection 4.1

4.1 Tetrapod origin

If we turn to paleontology, we find a description of tetrapods appearance into three main steps. Appearance of chordates, segmentation of lateral fins, appearance of tetrapods.

That’s the shortest version one can get except “pouf they appeared”. Interesting nevertheless the second step, the “segmentation of lateral fins“. This is one of three hypothetical, not exclusive, working models. Not to be used as a granted fact (see below).

Good news, bad news.

Good news are that Fleury abandonned the idea it appeared in one of his conferences announcement, and promoted in fora, that the tetrapods may have appeared suddenly, with all there attributes, specifying suddenly as “in a single generation“.

But he still think that:

These early tetrapods have well formed complex limbs apparently almost “right away”.

Almost right away being an estimate of the time-lapse between Haikouichthys ercaicunensis, presenting a single median fin-fold and tail, to the tetrapodomorph Tiktaalik roseae; almost right-away corresponds to 100 millions years. At least we are not anymore at the “single generation“level.

Progressive modifications are problematic for a model which is based on a suddenly appearing bauplan.

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geometry

I’m greek and during my young years I was feed a lot of geometry. You know how it is, national pride for the ancestors, especially under a military junta. So, I’m quite sensible when one presents geometrical problems incorrectly.

My very first objection concerning Fleury’s model¹ was that he described the epiblast cells as contained between two extracellular membranes. When I pointed that his only response was that if there is a single basal membrane that doesn’t affect his model, the flow would be just faster. From that point on you can’t trust the guy with any description.

Question

This is an old question which never received an answer. And certainly an answer wasn’t required before the publication of cteappv. As everything in the paper is about clarification and one more particular point remain unclear, I’ll post my question here and maybe Vincent Fleury will be kind enough to provide an answer.